LS1 6 speed into 67 A- body

I have a 67 buick special and i've been trying to come up with something different than the normal 455 type transplant. I located a 2000 TA engine and 6 speed complete with computer and harness for 4 grand. Just wondering what the real scoop is on the trans tunnel. does it need to be modified? do i have to run cats on this engine to prevent throwing codes? I'm only thinking about this swap right now but the additional info would sure help.

Go for it. I ditched my 455 and installed a ls1 a4 in my 65 cutlass. No regrets it is awesome to say the least and gets 22+ mph to boot. Yes you will have to mod your trans tunnel for the 6 speed. Several 67 A-body guys on here I'm sure they will join in shortly. Don't sweat the wiring it is actually the easiest part of the swap.
Good luck with your project it's a blast to do.
Rocky

I would say 4 grand for an engine and harness isn't that great of a deal even if it is low mileage. As far as cats go you can have them tuned out as somebody else mentioned so no problems there and yes you will have to mod the tunnel as rockytopper pointed out. That is definitely a slick buick that would make a great sleeper swap.